When investing in the stock market the value of your investment can go up and down at any time. You could get back less than you put in.
The factors affecting your investment value can be varied, including global politics, environmental events, investor behaviour (general behaviour of people pulling out of / adding money into the market), recessions and more. The performance of your portfolio will be affected (not exclusively) by (A) the general movement of the stock market and (B) macro economic factors.
Remember that for those looking to grow their wealth with CIRCA5000, it's best to think in terms of years (at least 3-5 years) not days, weeks or even months. History suggests that those who do best at growing their wealth through investing are the ones that have left their money alone in the market for a long time. It's incredibly hard to perfectly time the market, so we always advocate thinking long-term and investing regularly to smooth out the natural rises and falls in the market.
If you're unsure if investing is right for you please seek advice from a suitably qualified adviser. CIRCA5000 does not offer investment advice.